brennan tried to allay concerns and talked about new procedure and said that in the past year there have not been a single collateral death because of the exceptional efficiency and provision -- decision of the capabilities they been able to develop. they say no one has been killed. >> so have they delivered on that envisioned? >> this is where the new research comes in here it has been done by the bureau of investigative journalism, which is a non-profit organization of journalists that dig into this kind of thing. they had done some work on strikes carried out since august 23, 2010, which is when they did a particular strike when the u.s. changes its policy. they say that by their reckoning, 45 people, civilians who were not militants or key figures in the leadership of al qaeda with the taliban, were killed during that time. looking at a for the theme, they would estimate another 60 and involve people were killed, making it well over 100 casualties. the u.s. has responded to the bureau of investigative journalism, saying that these are wildly off, these figures. they have rejecte